Tumor osteolysis in osteopetrotic mice

Details of the cellular and biochemical mechanisms involved in focal destruction of bone at sites of tumor osteolysis are unknown. It has been shown that tumors from sarcoma (2472) cell lines induce focal osteolysis in mice by stimulating formation and activation of osteoclasts. In this report, the influence of 2472 tumors on the skeletons of osteoclast-deficient animals (op/op) was studied. After op/op femora had been inoculated with 2472 cells, tumors developed and focal osteolysis occurred. There were more osteoclasts per histologic section in sham-injected femora (19 ± 5) than in tumor-bearing femora (412 ± 129) (p < 0.05). The size of the osteoclasts also increased from 304 ± 81 μm² in sham-injected limbs to 407 ± 62 μm² in tumor-bearing limbs (p < 0.001). Conditioned media from 2472 op/op tumor explants contained macrophage colony-stimulating factor. A deficiency of osteoclasts in op/op mice is the result of the absence of this factor; therefore, these data introduce the possibility that macrophage colony-stimulating factor derived from 2472 tumor may be responsible for directing osteoclast-mediated osteolysis at sites of the tumor.     

Evaluation of long-term safety of the anti-IgE antibody, omalizumab, in children with allergic asthma.

OBJECTIVE: To evaluate the long-term effects of the anti-IgE antibody omalizumab in children with asthma. METHODS: This was a 28-week, double-blind, randomized, placebo-controlled trial with a 24-week open-label extension. In the core trial 225 children (ages 6 to 12 years) with moderate-to-severe allergic asthma requiring inhaled beclomethasone dipropionate (BDP) received omalizumab every 2 or 4 weeks, and 109 received placebo. BDP dosage was stable for weeks 1 to 16, then reduced during weeks 17 to 24 using strict safety criteria. The lowest dose for optimal asthma control was maintained for 4 more weeks. During the 24-week extension, all patients (n = 309) received open-label omalizumab in addition to other asthma medications. One-year safety data were analyzed. RESULTS: The incidence of adverse events in patients treated with omalizumab for 52 weeks was similar to those treated for 28 weeks in the core trial, which was generally comparable with placebo. In the 52-week omalizumab group, upper respiratory tract infection and headache were the most frequently reported adverse events (47.1% and 42.7%, respectively). Eleven patients (4.9%) reported urticaria, which resolved spontaneously or with antihistamine, except for 1 patient who was discontinued because of severe urticaria. No anaphylactic reactions or adverse events suggestive of serum sickness or immune complex formation occurred. No anti-omalizumab antibodies were detected in any of the children. There is no evidence that new or more serious adverse events occur with long-term omalizumab treatment. CONCLUSIONS: Long-term treatment with omalizumab is safe and well tolerated in children with allergic asthma.     

Hepatic DNA adduct dosimetry in rats fed tamoxifen: a comparison of methods

Liver homogenates from rats fed tamoxifen (TAM) in the diet were shared among four different laboratories. TAM-DNA adducts were assayed by high pressure liquid chromatography-electrospray tandem mass spectrometry (HPLC-ES-MS/MS), TAM-DNA chemiluminescence immunoassay (TAM-DNA CIA), and (32)P-postlabeling with either thin layer ((32)P-P-TLC) or liquid chromatography ((32)P-P-HPLC) separation. In the first study, rats were fed a diet containing 500 p.p.m. TAM for 2 months, and the values for measurements of the (E)-alpha-(deoxyguanosin-N(2)-yl)-tamoxifen (dG-N(2)-TAM) adduct in replicate rat livers varied by 3.5-fold when quantified using 'in house' TAM-DNA standards, or other approaches where appropriate. In the second study, rats were fed 0, 50, 250 or 500 p.p.m. TAM for 2 months, and TAM-DNA values were quantified using both 'in house' approaches as well as a newly synthesized [N-methyl-(3)H]TAM-DNA standard that was shared among all the participating groups. In the second study, the total TAM-DNA adduct values varied by 2-fold, while values for the dG-N(2)-TAM varied by 2.5-fold. Ratios of dG-N(2)-TAM:(E)-alpha-(deoxyguanosin-N(2)-yl)-N-desmethyltamoxifen (dG-N(2)-N-desmethyl-TAM) in the second study were approximately 1:1 over the range of doses examined. The study demonstrated a remarkably good agreement for TAM-DNA adduct measurements among the diverse methods employed.     

Thalamic and cortical projections to middle suprasylvian cortex of cats: constancy and variation

 We investigated the constancy and variability in the numbers of thalamic and cortical neurons projecting to cat middle suprasylvian (MS) visual cortex. Retrograde pathway tracers were injected at a single anatomically and physiologically defined locus in MS cortex. Counts of labeled neurons showed that the visual thalamic projections to MS cortex consistently arose from a fixed set of nuclei in relatively constant proportions. In contrast, counts of cortical neurons revealed that transcortical inputs to MS cortex were much more variable. This differential variability may be linked to the developmental program, which affords greater influence of experiential factors on cortical pathway development than on thalamocortical pathway development. These results have implications for the development of models of cerebral connectivity that include measures of pathway variability. Received: 29 March 1996 / Accepted: 3 September 1996     

Infant feeding and overweight in two Oxfordshire towns

In a study of feeding and growth in the first year of life in two Oxfordshire market towns, the frequency of overweight babies was the same for the 'intervention' town (where a research health visitor gave intensive advice to mothers on feeding) as for the control town. Eighteen per cent of bottle-fed infants and three per cent of those breast fed were overweight at one year. It seems that an increase in the number of health visitors does not affect the frequency of overweight infants, but it may be that a greater emphasis on breast feeding might reduce the frequency.     

The effect of hydrolytic enzymes on the acetylcholine sensitivity of the skeletal muscle cell membrane

Isometric tension developed by rat soleus and extensor digitorum longus (EDL) muscles in response to acetylcholine (Ach) applied in vitro was recorded. Tension of contractures elicited in response to Ach increased after muscles had been incubated with phospholipase C, pepsin, or soluble fractions prepared from muscle homogenate.Using intracellular microelectrodes, resting membrane potential (RMP) and depolarisation in response to Ach added to the bathing medium were recorded in endplate-free regions of the muscle fibres. No significant change in RMP was observed in muscles incubated with soluble muscle fraction or phospholipase C, but depolarisation in response to Ach or carbachol was significantly increased. The time course for the increase in depolarisation and the contracture response to Ach was similar.When all available receptors were blocked with -bungarotoxin prior to incubation so that no response to Ach could be elicited, with subsequent incubation in muscle soluble fraction or phospholipase C, both contractures and depolarisation in response to Ach returned. These results support the hypothesis that receptors, not previously available to interact with Ach or -bungarotoxin were revealed following incubation.